1. Field of the Invention
The present invention relates to a power module used as a power controller, and its manufacturing method.
2. Description of the Background Art
A power module used as a power controller such as a three phase inverter generally includes a power semiconductor device performing switching, and a control board for driving the power semiconductor device.
The power semiconductor device and the control board are electrically connected with relay terminals. More specifically, relay terminals which have previously been electrically connected to the power semiconductor device are caused to penetrate through holes in the control board and soldered to the control board to establish an electrical connection between the power semiconductor device and the control board.
Prior art documents relating to the present invention include the following: Japanese Patent Application Laid-open Nos. 2004-87605, 2004-22705, and 9-293941 (1997).
Conventional power modules have problems such as difficulty in causing relay terminals to penetrate through holes in a control board due to a little freeplay in the diameter of the through holes in the control board relative to the diameter of the relay terminals.
Especially, there are cases in which in the process of causing the relay terminals to penetrate the through holes in the control board, the relay terminals fail to enter the through holes in the control board and then are bent against the surface of the control board. Such bends make more difficult the penetration of the relay terminals into the through holes in the control board and accordingly will require modification of the shape of the relay terminals. This complicates the manufacturing process.
Even if there is no bend in the relay terminals, there are also cases in which the relay terminals are formed in slightly deviated positions and thus less likely to enter the through holes in the control board.